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参数资料
| 型号： | ISL8102EVAL1 |
| 厂商： | Intersil |
| 文件页数： | 15/27页 |
| 文件大小： | 0K |
| 描述： | EVAL BOARD 1 FOR ISL8102 |
| 标准包装： | 1 |
| 系列： | * |
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ISL8102
ISL8102 INTERNAL CIRCUIT
EXTERNAL CIRCUIT
VCC
For example, a regulator with 450kHz switching frequency
having REF voltage set to 1.2V has T SS equal to 3.55ms.
A 100mV offset exists on the remote-sense amplifier at the
beginning of soft-start and ramps to zero during the first 640
POR
PVCC
+ 12 V
cycles of soft-start (704 cycles following enable). This
prevents the large inrush current that would otherwise occur
should the output voltage start out with a slight negative
CIRCUIT
ENABLE
COMPARATOR
+
-
0.66V
10.7k Ω
ENLL
1.40k Ω
bias.
During the first 640 cycles of soft-start (704 cycles following
enable) the DAC voltage increments the reference in 25mV
steps. The remainder of soft-start sees the DAC ramping
with 12.5mV steps.
The ISL8102 also has the ability to start up into a
pre-charged output as shown in Figure 12, without causing
SOFT-START
AND
FAULT LOGIC
FIGURE 11. POWER SEQUENCING USING THRESHOLD-
SENSITIVE ENABLE (ENLL) FUNCTION
2. The voltage on ENLL must be above 0.66V. The EN input
allows for power sequencing between the controller bias
voltage and another voltage rail. The enable comparator
holds the ISL8102 in shutdown until the voltage at ENLL
rises above 0.66V. The enable comparator has 100mV of
hysteresis to prevent bounce.
3. The driver bias voltage applied at the PVCC pins must
reach the internal power-on reset (POR) rising threshold.
In order for the ISL8102 to begin operation, PVCC is the
only pin that is required to have a voltage applied that
exceeds POR. Hysteresis between the rising and falling
thresholds assure that once enabled, the ISL8102 will not
inadvertently turn off unless the PVCC bias voltage drops
substantially (see”Electrical Specifications” on page 5).
any unnecessary disturbance. The FB pin is monitored
during soft-start, and should it be higher than the equivalent
internal ramping reference voltage, the output drives hold
both MOSFETs off. Once the internal ramping reference
exceeds the FB pin potential, the output drives are enabled,
allowing the output to ramp from the pre-charged level to the
final level dictated by the reference setting. Should the
output be pre-charged to a level exceeding the reference
setting, the output drives are enabled at the end of the
soft-start period, leading to an abrupt correction in the output
voltage down to the “reference set” level
OUTPUT PRECHARGED
ABOVE DAC LEVEL
OUTPUT PRECHARGED
BELOW DAC LEVEL
When each of these conditions is true, the controller
immediately begins the soft-start sequence.
Soft-Start
During soft-start, the DAC voltage ramps linearly from zero
to the programmed level. The PWM signals remain in the
high-impedance state until the controller detects that the
GND>
GND>
T1 T2
T3
V OUT (0.5V/DIV)
ENLL (5V/DIV)
ramping DAC level has reached the output-voltage level.
This protects the system against the large, negative inductor
currents that would otherwise occur when starting with a
pre-existing charge on the output as the controller attempted
to regulate to zero volts at the beginning of the soft-start
cycle. The Output soft-start time, t SS , begins with a delay
period equal to 64 switching cycles after the ENLL has
exceeded its POR level, followed by a linear ramp with a rate
determined by the switching period, 1/F SW .
FIGURE 12. SOFT-START WAVEFORMS FOR ISL8102-BASED
MULTI-PHASE CONVERTER
Fault Monitoring and Protection
The ISL8102 actively monitors output voltage and current to
detect fault conditions. Fault monitors trigger protective
measures to prevent damage to the sensitive load. One
common power good indicator is provided for linking to
external system monitors. The schematic in Figure 13
t SS = --------------------------------------------
64 + DAC ? 1280
F SW
15
(EQ. 12)
outlines the interaction between the fault monitors and the
power-good signal.
FN9247.1
July 28, 2008
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL8102IRZ | 功能描述:IC REG CTRLR BUCK PWM VM 32-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:100% 电源电压:8.2 V ~ 30 V 降压:无 升压:无 回扫:是 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:0°C ~ 70°C 封装/外壳:8-DIP（0.300"，7.62mm） 包装:管件 产品目录页面:1316 (CN2011-ZH PDF) |
| ISL8102IRZ-T | 功能描述:IC REG CTRLR BUCK PWM VM 32-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:100% 电源电压:8.2 V ~ 30 V 降压:无 升压:无 回扫:是 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:0°C ~ 70°C 封装/外壳:8-DIP（0.300"，7.62mm） 包装:管件 产品目录页面:1316 (CN2011-ZH PDF) |
| ISL8103 | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Three-Phase Buck PWM Controller with High Current Integrated MOSFET Drivers |
| ISL8103CRZ | 功能描述:IC REG CTRLR BUCK PWM VM 40-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:100% 电源电压:8.2 V ~ 30 V 降压:无 升压:无 回扫:是 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:0°C ~ 70°C 封装/外壳:8-DIP（0.300"，7.62mm） 包装:管件 产品目录页面:1316 (CN2011-ZH PDF) |
| ISL8103CRZ-T | 功能描述:IC REG CTRLR BUCK PWM VM 40-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:100% 电源电压:8.2 V ~ 30 V 降压:无 升压:无 回扫:是 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:0°C ~ 70°C 封装/外壳:8-DIP（0.300"，7.62mm） 包装:管件 产品目录页面:1316 (CN2011-ZH PDF) |
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